Electric pneumatic impact mechanism

Abstract

1. The camshaft of claim 1, wherein the camshaft is mounted on a pivotal portion of the camshaft and is adapted to move the camshaft relative to the drive housing. The camshaft is configured to move the camshaft relative to the drive housing. The camshaft is configured to move the camshaft relative to the drive housing. The camshaft is configured to move the camshaft relative to the drive housing. The camshaft is configured to move the camshaft relative to the drive housing.

Description

Technical Field

[0001] The present invention relates to an electropneumatic impact mechanism for a handheld electric power tool, particularly a hammer drill and / or a chisel hammer. The impact mechanism comprises a transmission housing, a guide tube at least partially disposed within the transmission housing, an excitation piston movable within the guide tube, a connecting rod coupled to the excitation piston, and an eccentric designed as an externally toothed gear. The eccentric is coupled to the connecting rod on one side and is rotatably mounted relative to the transmission housing on the other side. Background Art

[0002] Percussion mechanisms of the type mentioned at the outset and hand-held power tools having such a percussion mechanism are generally known from the prior art. Summary of the Invention

[0003] The object of the present invention is to provide an impact mechanism that can be used more flexibly.

[0004] This object is achieved by providing an axial gap between the eccentric surface facing the connecting rod and the connecting rod surface facing the eccentric. The axial gap is preferably used to accommodate the lubrication space separating element or at least a portion thereof. It has been found to be advantageous to provide a radial spacing between the contact point furthest from the axis of rotation in the radial direction and the tooth root circle of the eccentric, which is designed as an externally toothed gear, between the connecting rod and the eccentric. The radial spacing is preferably used to accommodate the lubrication space separating element or at least a portion thereof.

[0005] The present invention comprises the discovery that the optional introduction of a lubrication space separation element makes it possible to dispense with the lubrication space separation element, for example in markets where lubrication space separation is not required. In markets where lubrication space separation is required, a lubrication space separation element, possibly with a seal, can be introduced. By separating the impact mechanism lubrication space from the motor lubrication space, the lubrication of toothed parts (for example, between the pinion of the electric motor and the outer teeth of the eccentric) can be improved. In addition, this provides an improved sealing against rock and concrete dust, which in turn reduces the wear on the pinion-outer tooth pair or at least extends its service life. It is also conceivable that hand-held power tools and / or impact mechanisms to be delivered do not have a lubrication space separation element when they are first delivered, and that, depending on the type of use and wear, the lubrication space separation element is introduced during maintenance. By reducing the number of parts, costs and weight are saved in impact mechanisms and / or hand-held power tools without a lubrication space separation element.

[0006] In a particularly preferred embodiment, the axial play relative to the axial axis of rotation of the eccentric is at least 20 percent of the thickness of the eccentric in the axial direction. It has been found to be advantageous if the axial play is at least 5 mm. It has been found to be advantageous if the radial distance between the contact point and the root circle is at least 5 percent of the root circle diameter (FD) of the root circle. It has been found to be advantageous if the radial distance is at least 5 mm.

[0007] In a particularly preferred embodiment, preferably for specific markets, the impact mechanism has a lubrication space separating element, which is accommodated in the axial gap and / or the radial spacing. It has been found to be advantageous if the lubrication space separating element has an annular sealing collar with a dynamic sealing ring, which is arranged coaxially with respect to the axis of rotation and presses against the radial spacing.

[0008] In a further preferred embodiment, the lubrication space separating element comprises an end sealing collar that at least partially seals the eccentric relative to the housing wall. The end sealing collar can comprise a static sealing ring that is arranged coaxially with respect to the axis of rotation and presses against the inner edge of the transmission. In a further preferred embodiment, the lubrication space separating element comprises a sleeve-shaped sealing chamber for receiving the pinion of the electric motor. It has been found to be advantageous if the annular sealing collar, the end sealing collar, and the sealing chamber are integrally formed.

[0009] In a particularly preferred embodiment, the lubrication space separation element is free from the influence of axial support loads caused indirectly or directly by the connecting rod. Advantageously, the height of the annular sealing ring is smaller than the axial gap in the axial direction. In a particularly preferred embodiment, the cover shell has a retaining lip on the side facing the eccentric, which is used to fix the connecting rod in the axial direction. The contour of the retaining lip preferably follows the circular path of the eccentric point of the eccentric at least in part. A plurality of retaining lips can be provided, each retaining lip being arranged concentrically relative to each other. The diameters of the retaining lips can be different from each other. The closing cover can have a supporting collar, which extends in the axial direction and stands upright on the end sealing collar in the axial direction.

[0010] This object is also achieved by a handheld electric power tool, in particular a hammer drill and / or a chisel hammer, having an impact mechanism as described above. It has been found advantageous if the handheld power tool has an electric motor with a pinion for directly driving the eccentric via its external teeth. The pinion and the external teeth of the eccentric can be located in the motor lubrication space. In a further preferred embodiment, the surface portion of the connecting rod and / or eccentric facing the cover housing is accommodated in the impact mechanism lubrication space, which is hydraulically separated from the motor lubrication space.

[0011] The object is also achieved by a lubrication space separation element having an annular sealing collar, an end sealing collar and a sealing chamber which are formed integrally with one another.

[0012] Further advantages will become apparent from the following description of the accompanying drawings. Various exemplary embodiments of the present invention are illustrated in the accompanying drawings. The drawings, the description, and the claims contain many combined features. Those skilled in the art will readily consider these features individually and combine them to form further useful combinations. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In the accompanying drawings, the same and similar components are denoted by the same reference numerals. Specifically:

[0014] Figure 1 A preferred exemplary embodiment of the impact mechanism according to the invention is shown. DETAILED DESCRIPTION

[0015] Figure 1 A first preferred exemplary embodiment of an electro-pneumatic impact mechanism 70 for a handheld electric power tool is shown.

[0016] The electropneumatic impact mechanism 70 includes a transmission housing 60 and a guide tube 50, wherein the guide tube 50 is at least partially disposed within the transmission housing 60. The electropneumatic impact mechanism 70 also includes an excitation piston 40 movable within the guide tube 50, a connecting rod 30 coupled to the excitation piston 40, and an eccentric 20. The eccentric 20 is coupled to the connecting rod 30 on one side and is rotatably mounted relative to the transmission housing 60 about a rotation axis DA via an end plate 10 of the transmission housing 60 on the other side. The end plate 10 is integrated into the transmission housing 60. The eccentric 20 is rotatably mounted on a bearing body 25 via a pair of sliding bearings 28. The bearing body 25 is incorporated into the end plate 10 for rotation therewith. The eccentric 20 is designed as an externally toothed gear that can be rotationally driven by an electric motor 90. To this end, the electric motor 90 includes a pinion 91 that mates with the external teeth 29.

[0017] As from Figure 1 It can be seen that the axial gap AS is provided between the eccentric surface EO facing the connecting rod 30 and the connecting rod surface facing the eccentric 20. The axial gap AS based on the rotation axis DA of the eccentric 20 in the axial direction AR is, for example, approximately 30 percent of the thickness DE of the eccentric 20 in the axial direction AR. Figure 1It is understood that the radial distance RA is provided between the contact point furthest from the axis of rotation DA in the radial direction RR between the connecting rod 30 and the eccentric 20 and the root circle FK of the external teeth 29. This contact point is located between the connecting rod 30 and the eccentric 20. The radial distance RA between the contact point and the root circle FK is, for example, five percent of the root circle diameter FD of the root circle FK of the eccentric. The connecting rod 30 has a connecting rod pin 31 that engages in the eccentric 20. The contact point is located at the transition from the connecting rod pin 31 to the eccentric 20.

[0018] Inside the transmission housing 60, the striking mechanism 70 has a lubrication chamber separating element 80 that hydraulically separates the motor lubrication chamber 92 from the striking mechanism lubrication chamber 62. The pinion 91 and the external teeth 29 of the eccentric 20 are located in the motor lubrication chamber 92. The connecting rod 30 and the wheel surface facing the cover 65 (whose diameter preferably corresponds at most to the root diameter FK) are accommodated in the striking mechanism lubrication chamber 62, which is hydraulically separated from the motor lubrication chamber 92.

[0019] The lubricating space separating element 80 itself has an annular sealing collar 81, an end sealing collar 83 and a sealing chamber 85. In the exemplary embodiment shown here, the annular sealing collar 81, the end sealing collar 83 and the sealing chamber 85 are formed integrally with each other. The lubricating space separating element 80 is, for example, made of plastic.

[0020] An annular sealing collar 81 serves to seal the eccentric 20 on the side facing the cover housing 65 . To this end, the annular sealing collar 81 is accommodated in the axial gap AS between the connecting rod 30 and the eccentric 20 , in the axial direction AR. The annular sealing collar 81 rests, so to speak, on the radial distance RA, in the radial direction RR. The axial gap AS and the radial distance RA are thus occupied by a single, separate element in the form of the annular sealing collar 81. The annular sealing collar 81 is provided with a dynamic sealing ring 82 , which is arranged coaxially with respect to the axis of rotation DA and presses against the radial distance RA.

[0021] The end sealing collar 83 serves to at least partially seal the eccentric 20 relative to the housing wall 68. For this purpose, the end sealing collar 83 has a static sealing ring 84 which is pressed against the housing wall 68 in the axial direction AR. Figure 1 The static sealing ring 84 in the exemplary embodiment of FIG. 1 is arranged coaxially with respect to the axis of rotation DA in the region of the eccentric 20. In the region of the pinion 91, the static sealing ring 84 is also pressed against the housing wall 68 in the axial direction AR. However, in this region, the sealing ring 84 extends coaxially with respect to the axis of rotation RO of the pinion 91.

[0022] The sleeve-shaped sealed chamber 85 of the lubricating space separating element 80 is ultimately used to accommodate a pinion 91 of an electric motor 90 .

[0023] If you can Figure 1 It is known that the transmission housing 60 is closed on the upper side 61 by a cover 65, which is composed of plastic, for example, and starting from the upper side, in particular the connecting rod 30 and the eccentric 20 are introduced into the transmission housing 60. The cover 65 has a retaining lip 67 on the side 63 facing the eccentric 20, wherein the contour of the retaining lip 67 follows the circular path 23 of the eccentric point 21 of the eccentric 20. Figure 1 In the exemplary embodiment of the present invention, four retaining lips 67 are provided, which are concentric relative to each other and each have a different diameter. The retaining lips 67 serve to fix the connecting rod 30 in the axial direction AR.

[0024] The connecting rod 30 also secures the eccentric 20 in the axial direction AR via the annular contact portion 33 of the connecting rod pin 31 in the eccentric 20, with the contact point also located on this annular contact portion 33. The cover 65 is therefore directly responsible for securing the connecting rod 30 and indirectly (via the connecting rod 30) securing the eccentric 20 in the axial direction AR. The power flow described here is managed without the "help" of the lubricating space-separating element 80. In other words, even without the lubricating space-separating element 80, the connecting rod 30 and the eccentric 20 are axially secured, allowing the lubricating space-separating element 80 to be omitted if desired (for example, if not required by law).

[0025] exist Figure 1 In the exemplary embodiment of the present invention, a lubricating space separation element 80 is provided. Figure 1 As can be seen, the cover 65 includes a support collar 66 that extends in the axial direction AR and stands upright on the end sealing collar 83 in the axial direction AR, thereby also exerting a compressive force on the static sealing ring 84 in the axial direction AR. The lubrication space separating element 80 itself is thus retained in the transmission housing 60. In addition to the aforementioned power flow without the lubrication space separating element 80, the introduction of the lubrication space separating element 80 provides additional axial fixation of the eccentric 20, namely, indirectly via the dynamic sealing ring 82 of the annular sealing collar 81, which is integrally formed with the end sealing collar 83. Advantageously, the height of the annular sealing collar 81 is slightly smaller than the axial gap AS, and the annular sealing collar 81, and therefore the entire lubrication space separating element 80, is unaffected by axial support loads caused indirectly or directly by the connecting rod 30. The lubrication space separating element 80 can thus be surrounded by the impact mechanism 70.

[0026] Reference Signs List

[0027] 10 end plates

[0028] 20 eccentric wheel

[0029] 21 eccentric points

[0030] 23 Circular Path

[0031] 25 bearing body

[0032] 28 sliding bearing pairs

[0033] 29 external teeth

[0034] 30 connecting rod

[0035] 31 connecting rod pin

[0036] 33 Contact Department

[0037] 40 Incentive Piston

[0038] 50 guide tube

[0039] 60 transmission housing

[0040] 61 upper side

[0041] 62 impact mechanism lubrication space

[0042] 63 facing sideways

[0043] 65 cover

[0044] 66 support ring

[0045] 67 retention lip

[0046] 68 shell wall

[0047] 70 impact mechanism

[0048] 80 lubrication space separation element

[0049] 81 annular sealing ring

[0050] 82 dynamic seal

[0051] 83 end sealing ring

[0052] 84 static seal

[0053] 85 sealed chamber

[0054] 90 electric motor

[0055] 91 small gear

[0056] 92 motor lubrication space

[0057] AR axial direction

[0058] AS axial clearance

[0059] DA eccentric wheel rotation axis

[0060] DE eccentric wheel thickness

[0061] EO eccentric wheel surface

[0062] FK tooth root circle

[0063] FD root diameter

[0064] RA radial spacing

[0065] RO pinion's axis of rotation

[0066] RR radial direction

Claims

1. An electro-pneumatic impact mechanism (70) for a handheld electric power tool, wherein: The impact mechanism (70) comprises: a transmission housing (60); a guide tube (50) which is at least partially arranged in the transmission housing (60); an excitation piston (40) which is movable in the guide tube (50); a connecting rod (30) which is connected to the excitation piston (40); and an eccentric (20) which is designed as an externally toothed gear and is connected to the connecting rod (30) on one side and is rotatably mounted relative to the transmission housing (60) about a rotation axis (DA) on the other side. wherein an axial gap (AS) for receiving at least a portion of the lubrication space separating element (80) is provided between an eccentric surface (EO) facing the connecting rod (30) and a connecting rod surface facing the eccentric (20), and wherein, A radial spacing (RA) for receiving at least a portion of a lubricating space separation element (80) is provided between a contact point that is furthest from the axis of rotation (DA) in a radial direction (RR) and a tooth root circle (FK) of the eccentric (20), the contact point being between the connecting rod (30) and the eccentric (20), wherein the impact mechanism (70) has a lubricating space separation element (80) received in the axial gap (AS) and the radial spacing (RA), characterized in that the lubricating space separation element (80) has an annular sealing collar (81) for sealing the eccentric on the side of the eccentric (20) facing the cover shell (65), an end sealing collar (83) for at least partially sealing the eccentric (20) relative to the housing wall (68), and a sealing chamber (85) for receiving a pinion (91) of an electric motor (90).

2. The impact mechanism (70) according to claim 1, It is characterized by: The axial clearance based on the rotation axis (DA) of the eccentric (20) in the axial direction (AR) is at least 20 percent of the thickness of the eccentric (20) in the axial direction (AR).

3. The impact mechanism (70) according to claim 1 or 2, It is characterized by: The radial distance (RA) between the contact point and the root circle (FK) is at least 5 percent of the root circle diameter (FD) of the root circle (FK).

4. The impact mechanism (70) according to claim 1, It is characterized by: The annular sealing collar has a dynamic sealing ring (82) which is arranged coaxially with respect to the axis of rotation (DA) and is pressed against the radial distance (RA).

5. The impact mechanism (70) according to claim 1 or 4, It is characterized in that The end sealing collar has a static sealing ring (84) which is arranged at least partially coaxially with respect to the axis of rotation (DA) and which presses against the housing wall (68).

6. The impact mechanism (70) according to claim 1, It is characterized in that The annular sealing collar (81), the end sealing collar (83) and the sealing chamber (85) are formed integrally with each other.

7. The impact mechanism (70) according to claim 1 or 2, It is characterized in that The lubrication space separating element (80) is free from the influence of the axial support load caused indirectly or directly by the connecting rod (30).

8. The impact mechanism (70) according to claim 2, It is characterized by: The cover (65) has a retaining lip (67) on the side facing the eccentric (20), which is used to fix the connecting rod (30) in the axial direction (AR), wherein the contour of the retaining lip at least partially follows the circular path (23) of the eccentric point (21) of the eccentric (20).

9. The impact mechanism (70) according to claim 1 or 2, It is characterized by: The handheld electric power tool is a hammer drill and / or a chipping hammer.

10. A handheld electric power tool comprising the impact mechanism (70) according to any one of claims 1 to 9.

11. The handheld electric power tool according to claim 10, It is characterized by: The handheld electric power tool has an electric motor (90) having a pinion (91) for directly driving the eccentric wheel (20) via the outer teeth (29) of the eccentric wheel (20), wherein the pinion (91) and the outer teeth (29) of the eccentric wheel (20) are located in a motor lubrication space (92), and wherein the connecting rod (30) and the wheel surface of the eccentric wheel (20) facing the cover shell (65) are accommodated in an impact mechanism lubrication space (62), and the impact mechanism lubrication space is hydraulically separated from the motor lubrication space (92).

Images